Heat exchange apparatus



Nov. 28, 1939. w. c. KEERAN HEAT EXCHANGE APPARATUS rFi'led Jan. l.2, 1937 3 Sheets-Sheet 1 /UT WATER Nov. 2s, 1939.

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HEAT EXCHANGE APPARATUS Filed Jan, 2, 1937 l 3 Sheets-Sheet 5 @3&5-

Patented Nov. 28, 1939 HEAT"l EXCHANGEr APrAnAiriis y i Wimk, Cf Kegan mesne assignment x il); .1.; Il r xl.; o wi'. .1 Evanston Ill., assigner, by to Vapor yCar Heating Co.,

Application January- 2,1937, serial ifcii'in." (C1. 257-440) My invention*relates',v generally, toheat ex?v changeapparatus, and it has'particular relation to' indirect Waterheaters.` v f y, In manyinstances itis desirable to indirec'ti'y heat Water for domestic Vpurposes by using'heat obtained from' the hot Water ofv yaheating systememploying a'steain, hot'water, or vaporV boiler.. Ordinarily water systems 'of these kinds are main# n tained at a Xed temperature. Since it is prefer- 16"" able and more economical to employ a single' source of heat rather-than to provide an ainriliary source 'of heat for the domestic Water, it hasv been proposed to employ the hot water irornthe 1heating system to indirectly heat the vdonn-:Stic lfwater. The water lWhichis thus employed is usually'te'rmed"ffboiler Water, and by' means of an indirect Water heaterit is caused to heat the domestic water.

There are many types of'indirect Water heaters -2f')"that have'been proposed. All of 'these types, of

WhichI am aware, have one orinore serious disf advantages which make them undesirablev in certain'respectsv" W,

At the present time" there areonl'thema'rket indirect Water heaters which` comprise a coil'. of"copper tubing that is mountedfin a cast iron' casing.` The domestic Water flows through the coil andis heated by boilerA waterivhichis caused toflowthroiig'h the cast iron casef Since a coil 30is employed, rather'fthan straight unbent tubes,

there isa tendency'ior mineral vvdepositsy to, form froni'the Water on theroii'ghe'ne'd innersurface of the coil, the 'roue ened "surface beingcaused j, byjthe stresstof-Which"it is" subjectedI during ythe 35f;bendingoperatic ihetherthe'fcoil is 'gradual-` lylled up dueto thisl'cause'iorlto some other cause, it is"diff1cult, if not impossible; 'to clean outrthe coil, andit is,

therefore, necessary 'to replace'it "with a new; coil. Because of the'pron ycase, this'type of heater is heavy and, furthermore, itsl designis injlexible`, it ybeingnecessaryI to provide 'a'vfdifferentset ofv castings, 'formingvv thev case, forl each dilferent size of heater" `Foroperation, thistyp of heater Ki-irni'ist be placed inan upright positionj thereby requiring a relatively largev distance'betwe'en the v connections'to lthe boiler. This is a serious dis-1 advantage 'Whenthe heater is to, applied'jto y certain' types of modern boilers in lvrhilch the kverticall distance from` thefwater line tov the boiler' return 'is relatively shortpbOnly a small4 Water `'legj orv Water j acke'tisl requiredfin these- Y, newer 'types ofboilers dueto the improved fefl iiciency 'of modern construction. u *Y e Other types of indirect Waterl heaters a vision of t; e cast iron otherdisadvantages.

' ploy Astraight .tubes having'returnll "bends vat the ends which tend to causeth'e forriiation of mineral deposits? at "the 'bend` ari-d' Which "aref ooi' difficult, if not",'impossibl'e`,` to clearii Other lthe il' tub e's and casingjf made -of materials [hai/@f Sonieof these heaters emin` which:

straighten@ 'heaters having the tubes fastened rigidly Vat the ends in tube plates often have having different thermal kcoeficientsof expansion, With theresuit thatftheztubes `may breakloose from the' tube plates, thereby causing leakage.v

order to inspect or clean these Water heaters it is'fnecessary'to rst remove'. all of the pipe connections and then to take the heater entirely apart. 1

It' is, therefore, an object of frny invention to provide an indirect Water `heater which Willf not `have any' of these disadvantages "and *which Will.

be simple and efficient in operation( light in Weighnzand readily/and KAeconomically manu--y factnr-ed and installed. j s

An objectA of' my"nvention is to construct a heat exchanger in such manner that lits "water tight integrity will be maintained'regardless of the temperature to Whichitis subjected.

A further object of ,myinvention is 'to providea construction of indirect Watery heater in which 4 the fend castings areinterchangeablefor various sizes, 'and dierent capacities are obtained mere.'-

'ly-.by increasing the length ofthe tubes and casingjwl'ich may `beformed of stock. material? Another object of myv invention is to provide forinspecting,T and vcleaning the tubes of an'indirect water heater without removing anyv of the pipe connections thereto A still furtheru object of my invention is to pro# vide intake and exhaust boiler ports at'the same end ofthe casing of an'indirect vtvater heater. -An object'of my inventionis tocontrol the 'i now of heating' Water' through the case of an indirect VWaterr heate'r so that thewater constant- Vly ushessediment out ofy the case.l

yStill another obj'e'ct of my invention is toy cause the Water to be heated to 110W through the tubes of anY indirect `Water heater in a plurality of passes,` and to construct the baffles in the front andrear headers vin such manner as' to'prevent.

the formation of mineral deposits-'thereon from the water.

Other/,objects of my inventionwill, in part, be y obvious and in'part appear' hereinafter..

AMy' invention, accordingly, `is"disclosed in the" embodiment hereof Vshown in the accompanying drawings,l and it comprises the .featuresof'con-y struction", combination of elements, and arrange'n ment ofparts Which Will befexempliedin ther construction hereinafter set forth, andthe scope ofthe application of theappended claims.

`For a more complete` understanding, 'of the whichA will be indicated in nature and scope of my invention, reference may,P

`rbe' hadv to the'following detailed descriptionv taken in connection with the accompanying drawings,

Figure l is 'a' View, inside elevation, showing port ring il and it is connected by intake and the installation of my no-Vel indirect water heater and the connection thereof to a boiler and a storage tank;

Figure 2 is a longitudinal sectional View of the indirect water heater, illustrating in detail the features of construction;

Figure 3 is a view, in end elevation, of the front header;

Figure 4 is a View, in end elevation, of the front tube plate;

Figure 5 is a view, in end elevation, of the rear header;

Figure 6 is a View, in end elevation, of the rear tube plate; and

Figure '7 is a detail perspective View of the tubes and casing' of my novel indirect water heater. l

Referring now particularly to Figure 1 of the drawings, it will be observed that the reference `character i6 designates, generally, an indirect Water heater constructed in accordance with my invention. As illustrated, the indirect water heater le is provided with a boiler port ring l i that is arranged to be connected by inlet and exhaust pipes l2 and i3 to a boiler lil. It will be understood that any suitable type of steam, hot water or vapor boiler may be employed, and that the boiler I4 is shown merely for illustrative purposes. A front header l 5 is fastened to the boiler exhaust pipes i6 and Il to a suitable supply of domestic water to be heated, for example the hot water storage tank S8, which is connected to the city water supply line by an intake pipe I9 and which is connected to the service line and to the hot water xtures by the pipe 20. It will also be understood that the connections of the indirect water heater IQ to the domestic water supply system are merely illustrative and that other connections may be employed'without departing from the scope of my invention.

The4 details of construction of the indirect Water heater l are illustrated more clearly in Figure 2 of the drawings, to which reference will now be had. It will be observed that the boiler port ring Il is provided with intake and exhaust ports 24 and 25 to which the corresponding pipes l2 and i3 may be connected. Integrally formed with the boiler port ring il is a front tube plate 26, the purpose of Which will appear hereinafter. The boiler port ring H and the fronttube plate 26 are formed preferably of cast brass, bronze, or some metal having like characteristics, although it will be understood that other material may be employed if desired. A ange 2l is integral with the boiler port ring li for cooperating with a corresponding flange 2B integral with the front header i to provide a connection therebetween. Cap screws 28, extending through suitable iiange openings in the flange 28 into threaded openings in the flange 2l, fasten them together. A gasket 30 is provided between the flanges 2l and 28 to provide a water-tight connection.

The front header l5 is provided with intake and exhaust ports 32 and 33 for connection to the corresponding pipes i6 and I'Lshown in Figure 1 of the drawings. The front header l5 is formed preferably of cast brass, but it will be understood that any other suitable material may be employed within the scope of my invention.

At the other end of the indirect water heater i0, a rear tube plate 36 is provided having an integrally formed flange 3l to which a corre,- sponding flange 38 of a rear header 39 may be connected by cap screws 48 extending through suitable clearance openings in the flange 39 into suitable threaded openings in the flange 3l. A gasket 4l is positioned between the anges 31 and 33 to provide a water-tight connection therebetween. The rear tube plate 36 and the rear header 39 are formed preferably of cast brass, although other material may be employed if desred.

Interconnecting the front tube plate 26 and the rear tube plate 36 are tubes 43 through which the domestic water iiows to be heated. The ends of the tubes 43 are fastened rigidly into the front and rear tube plates 26 and 36 in order to provide a rigid connection therewith. This connection will, of course, be water-tight; Surrounding the tubes 43 is a casing 44, one end of which is secured rigidly, as by soldering, to the rear tube plate 36, while the. other end is secured rigidly in a like manner to the boiler port ring I l. Itis evident by this construction that the tubes 43 withstandthe entire longitudinal stress caused by the pres-Sure of the domestic water. The casing 46 itself is required to withstand only the bursting pressure of the boiler water, and this pressure is ordinarily limited to a maximum of about pounds per square inch. Since the casing 44 is under no longitudinal stress, the seal between it and the two plates 26 and 36 may have low tensile strength.

The tubes 43 and the casing 44 are formed preferably of copper, or at least they are formed of materials having substantially the same thermal coeicient of expansion. When so constructed there is substantially no relative expansion or contraction and consequently substantially no relative movement between the tubes @i3 and the casing 44 because of temperature change. lIf the tubes 43 and casing 44 were not constructed of materials having substantially the same thermal coefficients of expansion, it is entirely possible that either the tubes 43 would be broken loose from the tube plates 26 or 36, or that the casing 44 would be broken loose from the rear tube plate 3S or the boiler port ring l l.

Another distinct advantage, however, lies in this particular construction. ItV will be readily understood that the capacity of the Water heater l@ is determined by the area of its surface which is commonly in contact with-the boiler water on one side and the domestic water on the other. It will now be evident that the capacity of the water heater herein disclosed may be changed merely by altering the length of the tubes 43 and the casing 44. The tubes 43 are formed of standard copper tubing which is obtainable in the open market, cut to the various required lengths. Likewise, the casing 44 is formed of copper tubing :which also is available in the open market.

Therefore, the same end castings may be `employed with a variety of different lengths of tubes 43 and casings 4d to provide a range of heater capacities having a maximum number of interchangeable parts. Thus, for a given set of end castings, it 'is only necessary to provide tubes 43 and casingV 44 having different lengths. Moreover, since castings are employed only at the ends rather than to provide a complete housing for the tubes 43, the weights of the heater for different capacities are materially reduced.

Since the indirectwater heater lll is mounted in operation in a horizontal position, thedistance between the intake and exhaust ports 24 and 25 for the boiler water is a minimum. .As a result, an indirect water heater constructed in accordance with my invention may be employed with the modern type of boiler in which the water line of the boiler is low in relation to the return connection to the boiler. Only a suil'icient distance between the water level and the return connection is required to provide the connections to the diametrically opposite intake and exhaust ports 24 and 25, as will be readily understood.

The advantages of the horizontal type of in direct water heater disclosed herein will now be more readily apparent when the functioning thereof is compared to that `of an indirect water heater of the vertical type. As indicated hereinbefore, it is possible t take advantage of a relatively high temperature throughout the entire indirect heater when it is of the horizontal type, with the result that its eiciency is thereby improved. There is a much smaller difference in temperature of the boiler water that is available for heating the domestic water and, therefore, the domestic water is subjected to a relatively high temperature at all times. Consequently less heating surface is required in an indirect heater of the horizontal type thanis required for a heater of the same capacity of the vertical type.

With a view to causing aflushing action in the iiow of the boiler water in the casing 44, a bafe 45 is provided between the tubes 43, as is more clearly illustrated in Figure '1 of the drawings. One end of the baille 45 is positioned abutting the inner surface of the front tube plate 26,

while the other end is Aspaced from the inner surface of the rear tube plate 36. The boiler water is then caused to flow inaturbulent manner, as illustrated by the arrows in Figure 2 of the drawings, through the casing 44, and thus it imparts a maximum of heat to the domestic water in the tubes 43 and flushes sediment out of the case and back into the boiler.

It is desirable to have the domestic water pass through the tubes 43 in a plurality of passes, rather than to have v of the heater to the other and then back again. In order to cause the water to iiow through the heater in a plurality of passes, ther front header I is provided with a pair of partitions 46 and 41, as is illustrated more clearly in Figure 3 of the drawings. As there shown, the partitions 46 and 41 are so arranged as to provide three chambers in the front header I5. An intermediate chamber is formed between the two outer chambers which are connected, respectively, to the intake and exhaust ports 32 and 33. The gasket 30 is correspondingly shaped as shown in Figure 4 of the drawings, in order to seal these chambers one from the other.

In like manner, as illustrated in Figure 5 of the drawings, the rear header 39 is provided with a partition 48, thereby forming two chambers therein. The gasket 4I, shown in Figure 6 of the drawings, is correspondingly shaped to prevent direct flow of water between the chambers. As indicated by the arrows in Figures 2 and 7 of the drawings, the domestic water enters the intake port 32 and the lower chamber, formed by the partition 41 in the front header I5, and passes through the lowermost of the tubes 43 to the chamber formed by the baiile 48 in the rear header 39. The water then returns to the intermediate chamber between the partitions 46 and 41 in the front header I5, through thev next three tubes 43. 'I'he water then returns through through the exhaust port it pass only from one end the next two tubes to the upper chamber formed by the partition 48 in the rear header 39,` and then it returns through the uppermost tube 43 to the upper chamber formed by the partition 4G in the front header I5 from which it ows 33 to the water storage tank I8, or to the hot water piping system through the pipe 20.

It will be observed that the partitions 46, 41 and 48 are curved in one direction or another throughout their entire length. By so curving these partitions, no pockets` or corners are ,provided in which mineral deposits from the water might form which might eventually plug up the headers I5 and 39.

It will now be apparent thatall that is required to permit inspection of the tubes 43 is the removal of the rear header or inspection dome 39. By removing the cap screwsy 40 this header may be readily removed and the tubesv 44 will be open for inspection as indicated in Figure 6 of the drawings. To permit this inspection and cleaning, it is unnecessary to remove a single pipe connection to the boiler. port ring II or to the front header I5. As a result the necessary inspection and cleaning may be effected with a minimum of dismantling of either the heater I0 itself or of the pipe connections thereto. If desired, the pipes I6 and I1 may be removed from the front header I5 by means of unions, and this header may be removed by removing the cap screws 29. Both ends of the tubes 43 will then be open for inspection and cleaning if it is deemed necessary to go to this extent in dismantling the heater I0 and its connections. However, for most purposes, it is only necessary to remove the rear header 39.

Since certain changes may above construction and different embodiments of the invention may be made without departing from the scope thereof, it is intended that all matter contained in theabove description, or shown in the accompanying drawings, shall be interpreted as illustrative, and sense.

I claim as my invention:

An indirect water heater comprising, in combination, a plurality rof straight smooth bore tubes, a continuous unperforated tubular casing surrounding said tubes, a rear tube plate rigidly fastened to one end of 'said tubes and casing, a rear header carried by said rear tube plate, a boiler port ring rigidly fastened to the other end of said casing and having boiler ports substantially diametrically opposite each other, a front tube plate rigidly connected to said ring and to the other endof said tubes, a front header fastened to said ring and having intake and exhaust ports therein, and partitions cooperating with said headers for directing the flow of water through said tubes in a plurality of passes; said tubes and casing having substantially the same thermal coefficient of expansion, and said tubes and casing constituting the sole connection between said rear tube plate onvthe one hand and said ring and front tube plate on the other hand whereby arange of different heat exchange capacities can be provided with the same size of front and rear headers and boiler port ring by using different lengths of tubes and casings depending upon the capacity required.

WILLIAM C. KEERAN.

not in a limiting be made in thev 

